3 large egg whites, room temperature
1/8 teaspoon salt
1/3 cup granulated sugar
1/2 cup powdered sugar
1/8 teaspoon peppermint extract
red food coloring
Preheat oven to 200°F. Line a baking sheet with parchment paper. Using an electric mixer, beat egg whites and salt on medium-high speed until white and foamy, about 1 minute. With mixer running, gradually add granulated sugar in 3 additions, beating for 2 minutes between each addition. Beat until firm peaks form, about 2 minutes longer. Add powdered sugar and peppermint extract; beat to blend, about 1 minute.
Dot coloring over surface of meringue; do not stir (the coloring will form swirls when piped). Spoon meringue into a pastry bag fitted with a 1/2" star tip. (alternatively, spoon into a plastic freezer bag, then cut 1/2" off 1 corner.) Twist top; pipe 1" rounds onto prepared sheet, spacing 1" apart.
Bake meringues until dry, about 2 1/2 hours. Then turn of oven, leave meringues inside and let cool completely (overnight) (meringues will crisp as they cool). DO AHEAD: Can be made 2 days ahead. Store airtight at room temperature between sheets of parchment or waxed paper.